The in vivo organization of gene expression is a major challenge in cell biology research. We will study the functional significance of nuclear organization in HeLa cells infected by the human DNA virus, Adenovirus (Ad). This research plan is focused Ad induced changes in two nuclear structures, nuclear domain 10 (ND 10) and interchromatin granule clusters (IGCs), and on the transport activities of viral shuttle proteins that move between the nucleus and the cytoplasm. ND10 is a nuclear structure that is disrupted in some human cancer cells, and following infection by different DNA viruses. IGCs contain splicing factors, poly(A) RNA, and in infected cells, virus RNA. IGCs may have an important role in RNA production or trafficking. The long-term goal of the project is to understand how activities such as DNA replication and gene expression are coordinated with the structural organization of the nucleus. We will make a step toward achieving this goal by studying virus reorganization of ND10 and IGCs and nucleocytoplasmic transport. In the first specific aim we will study the production and localization viral and cellular RNA relative to IGCs in infections by wild-type and mutant viruses. In the second specific aim we will investigate the roles of Ad shuttle proteins in promoting viral DNA replication and gene expression. We will analyze mutant viral proteins, and test the effect of inhibiting a specific transport pathway on the function of these proteins. In the third specific aim we will investigate the significance of ND10 reorganization by studying viral mutants. These studies are important because they will provide valuable information about how nuclear organization is related to function. By clarifying the role of nuclear organization in viral replication and gene expression we will gain important insights into its significance for replication and gene expression of the host cell. This will serve as a valuable platform for studying the inter-relationship between nuclear organization and aspects of replication and gene expression in development, cell differentiation, and cancer.